1. Field of the Invention
The present invention relates to a shadow mask, a method of manufacturing a shadow mask, and a method of manufacturing a display device using a shadow mask.
2. Description of the Related Art
Recently, an organic EL display device using an organic EL (electro-luminescent) element has been in practical use. In some cases, a vapor deposition method is employed at the time of forming an organic layer and a cathode electrode of the organic EL element. In order to form the above organic layer and cathode electrode in a desired shape, a shadow mask formed with multiple fine slits arranged in parallel is used. As display devices have higher definition and higher image quality, the development of the shadow mask is under way. The shadow mask is also called a vapor deposition mask or metal mask.
For example, JP2013-241667A discloses that a vapor deposition mask, formed by stacking a metal mask provided with slits and a resin mask provided with patterns prepared by vapor deposition in positions overlapping with the slits, is formed by photolithography, thus achieving higher definition of the processing accuracy of the vapor deposition mask.
JP2007-95411A discloses that, in a metal mask for organic EL for forming an organic EL layer on a substrate, a resin protrusion is provided on the outer perimeter of a display unit on the side facing the substrate at the time of vapor deposition, of the metal mask for organic EL, thus preventing the metal mask and the substrate from contacting each other and preventing damage to the substrate surface due to foreign matters and scratches.
JP2003-253434A discloses that, in a vapor deposition method in which a pattern is formed by bringing a vapor deposition mask in tight contact with the surface of a substrate and then depositing a vapor deposition material on the surface of the substrate via an opening in the vapor deposition mask from a vapor deposition source, the surface of the vapor deposition mask that faces the substrate surface is roughened by sandblasting, thereby preventing the separation of the vapor deposition material.